Ocean deoxygenation - A long predicted result of climate change

“Natural variations have obscured our ability to definitively detect this signal in observations. In this study, however, Schmidtko et al. synthesize all available observations to show a global-scale decline in oxygen that conforms to the patterns we expect from human-driven climate warming. They do not make a definitive attribution statement, but the data are consistent with and strongly suggestive of human-driven warming as a root cause of the oxygen decline. It is alarming to see this signal begin to emerge clearly in the observational data.” – Matthew Long, oceanographer at the National Centre for Atmospheric Research

A new study underscores once again that some of the most profound consequences of climate change are occurring in the oceans rather than on land. In recent years, incursions of warm ocean water have caused large die-offs of coral reefs and, in some cases, kelp forests. Meanwhile, warmer oceans have also begun to destabilize glaciers in Greenland and Antarctica and as they melt, these glaciers freshen the ocean waters potentially changing the nature of their circulation. Declining ocean oxygen can also worsen global warming in a feedback loop. In or near low oxygen areas of the oceans, microorganisms tend to produce nitrous oxide, a greenhouse gas. Thus the new study implies that production rates and efflux to the atmosphere of nitrous oxide will probably also have increased.

As climate change continues, ocean deoxygenation will continue with studies suggesting a loss of up to 7 percent of the ocean’s oxygen by 2100. At the end of the current paper, the researchers are blunt about the consequences of a continuing loss of oceanic oxygen saying that far-reaching implications for marine ecosystems and fisheries can be expected. 

Scientists have just detected a major change to the Earth’s oceans linked to a warming climate: https://www.washingtonpost.com/news/energy-environment/wp/2017/02/15/its-official-the-oceans-are-losing-oxygen-posing-growing-threats-to-marine-life/?utm_term=.a1a6b70ee5f8